112 



Ki<i. 95. The Black Blis- 

 ter-beetle, Kpicauta pennsyl- 

 viinica. Kiilarged as indicated. 

 (Bruner.) 



leaves of a great variety oi' plants, among vvhi(;h eorn is to he included. 



They are especially destructive to potatoes and tomatoes and cultivated 



flowers, but their injuiMcs to corn are usually uiiinipoi-lanf except when 



the j)laut is still ({uitc; small. The species 

 known to attack corn are the strijxHl blister- 

 beetle (Fig. 94, 97), yellow above, with black 

 stripes; the black blister-beetle (Fig. 95), solid 

 black throughout; and the margined blister- 

 beetle (Fig. 96), l)hick above, with a narrow 

 gray edge round each wing-cover except at the 

 base. 



The striped species was unusually al)ii!idant 

 in Michigan in late June and early .July of 1900, 

 and as the potatoes of that region had not yet 

 come up the beetles heavily attacked young 

 corn (about six inches high) and clover. They 

 are fond of pigweed {A maranlus) , and will feed 

 on it in the corn fields, as long as it lasts, 



without molesting the corn. The margined blistcM'-beetle exhibits a 



similar pn^ference. 



The black species is often very common on coimi late in the season, 



eating the leaves, the silk at the tip of th(> ear, and even the husks and 



the soft kernels beneath. It may pos- 

 sibly do soiue harm by destroying the 



silk l)efore the kernel is fertilized. The 



strijied blister-beetle has also been 



noticed eating corn silks. The corn 



leaf is eaten away by these beetles 



from the edges until only the midvein 



is k^ft. Potatoes, beets, and asters 



are among the principal cultivated 



plants attacked, but most gar- 



(l(Mi vegetables ai'c liable to injury by 



them. The black sp(>cies is esp(>cially 



common on blossoms of the goldenrod 



in fall. 



These blister-beetles are widely 



(listril)uted over the UnitcMl States 



east of the Rocky Mountains. 



Their life history is highly ]iecu- 



liar. The larvie ])ass through five distinct and unlike stages, all but the 



last of which are shown in Fig. 97. The \\ inter is passed in the fourth 



stage (Fig. 97, f/), in which the lar\'a is ina('ti\('. In the fifth stage it 



changes, in spring, to a jnipa of the usual form. The adults of the 



l''i(;. 9(). The Margined Blister-beeUe, 

 Kincdiitd inarninala. Enlarged as indi- 

 cated. 



